[TYPO3-dev] About empty cHash

[Steffen Kamper]

Hi Francois,

"Francois Suter" <fsuter at cobweb.ch> schrieb im Newsbeitrag 
news:mailman.1.1203440970.4796.typo3-dev at lists.netfielders.de...
> Hi all,
>
> I have made an extension which relies on 2 plugins (it's vge_tagcloud). 
> The first plugin (pi1) builds a tag cloud, the second (pi2) displays a 
> list of pages related to each keyword. The keyword and the related pages' 
> uid are passed as piVars in the URL pointing to the page where pi2 is 
> located.
>
> pi2 is a cached USER object and has $pi_checkCHash = true;
>
> However this is apparently not sufficient to avoid the empty cHash 
> problem. As far as I understand (after re-reading The mysteries of cHash 
> and looking around the mailing lists), this is because the cHash of the 
> links are not stored in the cache table. The reason - as I understand it - 
> is because the links are generated in pi1 but point to pi2. The links are 
> generated inside a stdWrap property inside pi1, which means I'm not 
> calling some of the tslib_pibase methods where one can tell that the cHash 
> should be stored.

that's new to me. cHash is added automatic if the link target is cached. If 
you link to a INT-Object there is no cHash calculated.
If you are in pi1 and want to use links for pi2 you can use a simple trick:

$this->prefixId      = 'tx_myext_pi2';
...(do pi_linkTP) ...
$this->prefixId      = 'tx_myext_pi1';


>
> One solution I found is to set to true the property useCacheHash of the 
> typolink, but this means I have the cHash in the URL, which I would rather 
> avoid. Is there any way around this?
>
setting this in typolink will force to calculate a cHash. But if target is 
not cached it's nonsense.

vg Steffen